In wire electric discharge machining apparatuses, a wire is supported by a lower arm and an upper arm. With the lower arm enclosed in a bellows being inserted in a machining bath, the lower arm and the upper arm are moved. Thus, the wire moves in a machining liquid, so that a workpiece is machined.
In such a wire electric discharge machining apparatus, one end of the bellows is fixed to a seal plate (shield plate) outside the machining bath so that the machining liquid does not leak through the place where the lower arm is inserted in the machining bath. Further, the machining liquid having leaked through the area adjacent to the seal plate is retrieved by a retrieving tub (refer to, e.g., Patent Literature 1).